Mr. Barren doesn’t think that all bad language should be allowed. In his opinion, there are that should be kept up.
A. degrees
B. levels
C. limits
D. standards
网友回答
A. degrees
B. levels
C. limits
(答案→)D. standards
解析：定语从句that should be kept up 中的keep up 表示“保持、维持、坚持”。根据前一句的逻辑推理：Barren 先生认为我们不能容忍所有骂人的话，可以推断出“需要维持一定的标准、准则。”